Device for sharpening reamers



3, 1934. K. BLEY 1,953,212

DEVICE FOR SHARPENING REAMERS Filed Nov. 29. 1952 2 Sheets-Sheet 1 Fig 7 April 3, 1934. BLEY 1,953,212 I DEVICE FOR SHARPENING REAMERS Filed Nov, 29. 1932 2 Sheets-Sheet 2 Fig 6 Patented Apr. 3, 1934 1 UNITED STATES PATENT oFricE Application November 29, 1932, Serial No. 644,846 In Germany November 7, 1931 3 Claims.

This invention relates to a device for sharpening the back blade faces of the ribs of reamers by means of reciprocating files. It is known in such arrangements to make the support guiding the 8 tool adjustable in height.

However, as it was not hitherto possible with the aid of a simple arrangement to effect a perfect adjustment of the file relative to the edge to be sharpened, the sharpening had to be carried out according to the judgment of the worker.

The known devices have a support for the file; as, however, reamers of different diameters have to be worked with one and the same device, the tool support can only be employed for workpieces of a certain diameter to correctly adjust the tool -relatively to the edge to be sharpened and to maintain the prescribed cutting angle.

These objections are overcome according to the invention in that the support for the file is vertically shiftable, so that it can be adjusted to suit different diameters of the reamers. For elfecting this adjustment in a simple manner a gauge is employed during the adjustment of the device. This gauge has two measuring bars. One bar is placed on a plane surface of the frame of the sharpening device and the other measuring bar on the edge of the reamer which is to be treated and on the adjustable support for the tool. It is then only necessary to adjust this support until the first mentioned measuring bar bears absolutely uniformly on the plane surface. The supporting bar is thereupon fixed and the edge can then be sharpened by placing the tool on the reamer and the supporting surface and moving it longitudinally and transversely.

For this purpose the tool is constructed so that the upper and lower sides of the handle lie in the same planes as the grinding surfaces.

To enable the grinding to be carried out with both hands the clamping device for the reamer is constructed so that this device can be fixed during the grinding and need not be held by hand.

This device can be employed for reamers both with straight edges and also for reamers with .spiral edges, the device can therefore be so con- "structed ihat the reamer is rotated during the grinding.

Two embodiments of the invention are illustrated by way of example in the accompanying drawings in which:-

Fig. 1 shows in side elevation the device for a simple reamer with straight edges.

Fig. 2 is a cross-section of Fig. 1.

Fig. 3 shows the support of the gauge.

Fig. 4 shows the file in side elevation on a. larger scale.

Fig. 5 shows the file in cross-section.

Figs. 6 to 8 show the second form of construction for reamers with spiral edges.

The device consists of a holder 1 bent in U- shape and carrying two sleeves 2 and 3 in which mandrels 4 and 5 are clamped by screws 6a and 6b. The mandrel 5 has a triangular or square point and bears against the reamer 9 under the pressure of a spring 7 which can be adjusted by a set ring 8. The polygonal point pressed in by the spring prevents the reamer from turning when being worked. On the under guide of the holder 1 an arm in slides which carries a resilient abutment 11, designed to'stand in front of the blade 12 of the reamer to be worked. A rotatable, eccentrically mounted supporting cylinder 13 is arranged on the other side of the holder.

The reamer is set in the following manner? 15 The mandrel 5 is first secured in position by means of the screw 61), whereupon the reamer is inserted, the second point 4 pressed against same and the screw 6a tightened, the screw 612 being then loosened so that the reamer is held by the pressure of the spring 7.

The adjusting of the filing device is effected by placing on the device a gauge 14 having the shape of a double T. One measuring arm 15 of the gauge 14 must rest flat on the plane surface 17 and the other arm 18 bear against the reamer 12 and rest on the supporting cylinder 13. The supporting cylinder is then turned until the arm 15 bears uniformly on the plane surface 17 so that a parallel adjustment is obtained. After removing the gauge the filing can commence.

The file consists substantially of one, or preferably two emery stones 19 and 20 of different degrees of fineness, which are cemented together and held in a frame 21 by means of screws 22. The frame has a handle 23 engaging in a bore in a support 24 provided with a handle 25. The support 24 is of elliptical cross-section. The large axis of the ellipse is of the same length as the stone (Fig. 5), so that the two working sur- 190, faces lie at the height of the guide edge on the support.

As, however, the stones wear in the course of time, provision must be made for the guide edge to always be situated at the same height. Consequently, the support is of elliptical or similar cross-section. Therefore it is only necessary, when the stone wears, to loosen the small fixing screw 26 and slightly turn the handle with the guide, so that the supporting edge is always li e;

brought to the height of the working surface of the stones.

For spiral reamers an arrangement similar in principle and illustrated in Figs. 4 to 8 is employed, which is only differently constructed in certain details. In this instance the holder 1 carries the two adjustable mandrels 4 and between Which the spiral reamer 27 is clamped. The frame carries on one side the rotatable cylinder 13 and on the other side a second guide bar 1311. Both parts serve as guide for a carriage 28, which bears with guide rollers 29 and 30 against the two bars. As, however, the position of the cylinder 13 is changed, the rollers 30 can be raised and lowered. For this purpose a joint 31 is provided in the carriage. The rollers 30 are then pressed against the guide bar by the springs 32. An adjustable finger 33 is fitted on the carriage and bears against the spiral surface of the reamer. If, therefore, the carriage is shifted on its guide, the reamer is rotated around its longitudinal axis by the guide finger. The tension of spring 34 must be such that the positive connection is maintained between the two elements during the return movement and the spiral spring returned into its initial position. For this purpose the spring 34 is connected at one end to the holder 1 and at its other end to a collar 35 of the v mandrel 5.

for supporting a gauge, a cylinder eccentrically mounted in said frame and adapted to serve as support for the gauge, holders on the arms of said frame, adjustable points mounted in said holders and adapted to carry the reamer, a spring acting on one of said points and adapted to press this point against the reamer, and an adjustable abutment on said frame adapted to bear against the teeth of the reamer.

2. A device for sharpening reamers, comprising in combination a U-shaped frame having on the upper side of one of its arms a plane surface for supporting a gauge, a cylinder eccentrically mounted in said frame and adapted to serve as support for the gauge, holders on the arms of said frame, adjustable points mounted in said holders and adapted to carry the reamer, a spring acting on one of said points and adapted to press this point against the reamer, an adjustable abutment on said frame adapted to bear against the teeth of the reamer, a frame shaped tool holder, emery stones in said tool holder, adapted to bear on said cylinder and the reamer, an extension of said tool holder, and a guide of elliptical cross-section rotatably carrying said extension.

3. A device for sharpening reamers, comprising a U-shaped frame having on the upper side of one of its arms a plane surface for supporting a gauge, an adjustable cylinder eccentrically mounted in said frame adapted to serve as gauge support, a carriage guided by said cylinder, conical guide rollers on said carriage bearing against said eccentric cylinder, a joint connecting said rollers with said carriage to allow said rollers to I the shifting of said carriage, and two tool guides V mounted on said carriage.

KURT BLEY. 

